Schmidt Number Calculator




The Schmidt Number (Sc) is a dimensionless parameter used to describe the rate of mass transfer in a fluid relative to the rate of momentum transfer or viscous flow. It is particularly important in situations where the diffusion of a substance within a fluid is a key process, such as in chemical reactions, environmental pollution dispersion, and heat transfer through convection. Understanding the Schmidt Number helps engineers and scientists predict how different substances will diffuse through a fluid and how fast they will do so.


The Schmidt Number (Sc) is defined by the following formula:

Sc = μ / (ρD)


  • Sc represents the Schmidt Number, a dimensionless quantity.
  • μ is the dynamic viscosity of the fluid.
  • ρ is the density of the fluid.
  • D is the diffusivity of the solute or substance being transferred in the fluid.

The Schmidt Number quantifies the ratio of momentum diffusivity (viscous forces) to mass diffusivity (diffusion forces) in the fluid. It is an essential parameter in solving mass transfer problems and predicting the behavior of solutes or substances in various fluid systems.

How to Use

Utilizing the Schmidt Number Calculator involves the following steps:

  1. Gather Fluid Properties: Collect the necessary fluid properties, including the dynamic viscosity (μ) and density (ρ) of the fluid in which mass transfer is occurring.
  2. Determine Diffusivity: Determine the diffusivity (D) of the solute or substance that is undergoing mass transfer within the fluid. This diffusivity value is typically provided in literature or can be calculated based on the specific solute and fluid.
  3. Access the Calculator: Open the Schmidt Number Calculator on your preferred device, such as a computer or smartphone.
  4. Input Parameters: Enter the values of dynamic viscosity (μ), density (ρ), and diffusivity (D) into the calculator.
  5. Calculate Schmidt Number: Click the calculate button to initiate the calculation process.
  6. Interpret the Result: The calculator will provide the Schmidt Number (Sc), which quantifies the relative rates of momentum transfer and mass transfer in the fluid.
  7. Analyze the Result: Use the calculated Schmidt Number to assess the behavior of solutes or substances in the fluid, predict mass transfer rates, and optimize processes.


Let’s illustrate the Schmidt Number Calculator with a practical example:

Suppose you are working on a chemical reaction in a water-based solution. The fluid properties are as follows:

  • Dynamic viscosity (μ) = 0.001 kg/(m·s)
  • Density (ρ) = 1000 kg/m³
  • The diffusivity (D) of the solute in water is 1.0 × 10⁻⁶ m²/s.

Using the formula:

Sc = μ / (ρD)

Sc = 0.001 kg/(m·s) / (1000 kg/m³ * 1.0 × 10⁻⁶ m²/s)

Sc = 10⁻³ / (10⁻³) = 1

In this example, the calculated Schmidt Number (Sc) is 1, indicating that the rate of momentum transfer and mass transfer is comparable in this system.


1. What does a high Schmidt Number imply? A high Schmidt Number suggests that the rate of momentum transfer (viscous forces) is much greater than the rate of mass transfer (diffusion forces) in the fluid. This is often observed in high-viscosity fluids.

2. What are some practical applications of the Schmidt Number? The Schmidt Number is used in various applications, including chemical engineering (mass transfer in reactors), environmental science (pollutant dispersion in water and air), and heat exchanger design (predicting heat transfer rates in fluids).

3. Can the Schmidt Number be used for gases as well as liquids? Yes, the Schmidt Number is applicable to both gases and liquids, provided that the fluid properties and diffusivity are appropriately considered.


The Schmidt Number Calculator is a valuable tool for engineers and scientists involved in fluid dynamics, mass transfer, and chemical processes. Understanding the Schmidt Number helps predict the behavior of solutes or substances in fluids, optimize mass transfer rates, and design efficient processes. Whether you’re working on chemical reactions, environmental modeling, or heat exchanger design, the Schmidt Number is a fundamental parameter that guides your analysis and decision-making. Its significance in characterizing the relative rates of momentum and mass transfer in fluids makes it an indispensable tool in various fields of science and engineering.

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